This study is a continuation of a program evaluating digital computer methods in the analysis of EEG in man for clinical psychopharmacology. The program has developed systematic methods of data reduction (using period analysis, amplitude integration, and power spectral density analysis), statistical processing of the data using multivariate statistics, and designed experiments to control vigilance, set, and placebo effects in volunteers. These methods are in use for the classification of psychoactive substances by EEG profiles in phase-I clinical psychopharmacology, and the measurement of dose-response characteristics in the evaluation of CNS bioavailability. The program is continuing to improve the methods, particulary the classification schemata, and to assess the relationships between EEG measures and blood levels.